The purpose of Core B, the Clinical Cohort of the Seattle Primary Infection Program (SeaPIP), is to provide a well-characterized cohort of patients with acute HIV-1 infection, who are followed longitudinally in a standardized manner, to address the virologic and immunologic questions outlined in Projects 1-3. The specimens from subjects, including plasma, serum, peripheral blood mononuclear cells obtained via leukapheresis, pulmonary alveolar macrophages obtained from induced sputum collection, genital secretions, and rectal biopsies will be used to characterize the virological, immunological, and clinical outcomes of acute HIV-1 infection with and without highly active antiretroviral therapy (HAART). Patient recruitment and follow-up for Core B will occur at the University of Washington Primary Infection Clinic (PIC). All PIC enrollees enter a prospective observational study (Protocol 002), and may also co-enroll in a treatment study of HAART (Protocol 001). The Specific Aims of Core B are to: 1) Identify, accrue, and retain 10 patients/year with acute HIV-1 infection; 2) Maintain follow-up of 25 high priority patients previously enrolled into the cohort with acute HIV-1 infection to characterize their long-term virological and immunological characteristics;and 3) Design, implement, complete, and report the results of high-quality, state-of-the-art clinical research studies of pathogenesis and treatment of acute-HIV-1, both within the SeaPIP and in collaboration with the HIV-1 Acute Infection and Early Disease Research Program (AIEDRP). To accomplish these goals, the PIC will have an active outreach and recruitment plan and enroll a patient population that is reflective of patients in Seattle acquiring HIV-1 infection. The experienced staff will follow established procedures for data collection and management, comply with all federal and local regulations about clinical studies, and maintain linkages with the community via our Community Advisory Board and outreach efforts.